This invention relates to apparatus for cutting material such as steel or the like using a plasma and, more particularly, to apparatus which is modularized to permit a wide flexibity in configuring the power supply, control and cooling equipment used in a plasma cutting operating. The modules comprising the apparatus are removably stackable to simplify changing from one configuration, for one cutting operation, to a new configuration for a different type cutting operation. The invention further includes novel electronics for achieving improvements in torch cutting and welding.
Plasma arc welding is well-known in the art and there are many and varied applications for use of plasma arc welding equipment. See, for example, U.S. Pat. Nos. 4,839,499, 4,590,357, 4,326,842, 4,280,042, and 3,988,566. It is not uncommon in a manufacturing operation for different welding equipment set-ups to be required. Thus, one set-up may require one type of cutting torch, necessitate use of a power supply capable of delivering a voltage and a current having one set of characteristics (i.e. single or multi-phase power, voltage and amperage levels, etc.), and a particular level of cooling. Another set-up may require a wholly different torch, power, and cooling configuration. Changing from one set-up to another has heretofore required a substantial amount of time to reconfigure torches, power supplies and cooling equipment. In manufacturing operations, this "down-time" adds to the overall cost of the product and reduces the volume of units produced. In the alternative, two or more sets of equipment can be utilized, this equipment being kept in a particular configuration for whatever operations have to be done. This, of course, increases equipment costs, work and storage space requirements, etc. And, even having a profusion of equipment does not insure that set-up changes will not have to be made. It would be advantageous if it were possible to have apparatus which was capable of performing a myriad of cutting operations but which was sufficiently flexible that the amount of equipment required is minimized, that reconfiguration time for changing set-ups is substantially reduced, and the equipment used will support many varied cutting operations.